As has already been indicated, the foundation of the hammer is a wooden molding. Over this is glued, in the machine, a strip of “underfelt,” which is long enough to cover about five and a half or six octaves of hammers, counting from the bass end upwards. The main felting is then laid over this, the thickest end being at the lowest bass. By means of the machines, now so generally used, it is possible to glue the entire underfelt and also the topäfelt, in one piece. The moldings are then separated and the operation is complete. It is customary to insert a small piece of wire, doubled over in a loop, through each hammer, in order to ensure further strength to the fastening.
As may well be imagined, the details of manufacture, of the quality of the felting, and of the dimensions of the completed hammers, require much care in their execution. Long practice, study, and experience have combined to render the specialists, who devote themselves to the preparation of hammers and hammer-felt, most excellently fitted to place upon the market the very finest productions of this kind.
There have been attempts made at various times to provide a hammer head, and a method of felting it, that would obviate the somewhat rapid deterioration caused by the pounding of the glued and compressed felt against the stiff steel wire strings. The felt, which requires to be compressed before it is glued on to the wooden molding, rapidly becomes altogether too hard. Moreover, the fastening of the felt to the molding is by no means really permanent. It has been suggested that the felt might properly be contained within a wooden shell which would extend as far along the sides of the felt as the wooden molding now reaches within it. The compressed sheet of felt would be forced into this shell and fastened therein so that it would always be protected by an outer wooden covering. Thus, not only would the fastening of the felt to the wood be reduced more secure, but the pounding upon the strings would not so rapidly assure the undue hardening of the felt. For there would not be the hard wooden base between which the strings and the felt is continually subjected to compression. The idea is good and undoubtedly will yet be recognized.
Details of the adjustment of the hammers to the rest of the action and of the preparation of them by the tone-regulator, for the better production of good and even tone, will be dealt with in the chapters upon action-and tone-regulating.
CHAPTER XII.
THE TOUCH MECHANISM.
As the hammer-idea evolved itself in the mind of Cristofori and the other experimenters who were contemporaneously bending their efforts towards the improvement of the dynamic possibilities of keyed instruments, we may be certain that much perplexity was caused them by the problem of providing some mechanism that should form the connecting link between the hammer and the key. We may understand how the ingenious Italian must have labored, with the picture of the dulcimer and its player continually in his mind, to obtain an efficient mechanical substitute for the uncertain stroke of the hand operated dulcimer-hammer, as well as the dynamically incapable harpsichord jack and quill. It is surprising to note, indeed, how early the present ruling principles of action-mechanism were elaborated by these pioneer workers. Cristofori, as we have already mentioned, obtained, ere he died, a complete check to the rebound of the hammer and a form of escapement that may be seen unaltered in essentials in surviving square pianofortes of the “English action” variety. We may further reflect that the invention of Backers, as improved by John Broadwood the First, remains today the approved mechanism of many English and other European grands. Not only is this so, but until the general adoption of the Steinway overstrung model, there existed German makers who were content to fit their moderate priced grands with a slightly modified form of the Viennese action invented by that remarkable woman Nanette Stein, afterwards Madame Streicher, the conspicuous feature of which was the mobility of the hammer-butt and the stationary condition of the jack. The fact that these early mechanisms remained satisfactory to performers until recent years is the best proof of the thorough and sure mechanical basis upon which they were designed.
It is not necessary to go into elaborate detail in describing these early actions. Reference to the accompanying cuts will be sufficient to lay bare their actuating principles. We may, however, observe that the radical difference of touch between the Viennese (Streicher) models and those of Broadwood (known as the English grand action) continued to be a source of annoyance to performers until the increasing technical demands of the modern virtuoso school and the improvements in wire-drawing and iron casting made inevitable the supersession of the very light Streicher action by the heavier, more durable and more efficient Broadwood English model, which continued in favor until within recent years.